SARA-N200 is not connecting

Hi,

I’ve been testing NB-IoT in Germany:
I am using the following procedure to connect to a cell:

AT+CFUN=1
AT+COPS=1,2,“OPERATOR_ID”

AT+CEREG? returns 0,2 (2: searching)

It keeps searching, but does not connect to a cell. It worked once but after that I haven’t got another connection.

IMSI can be read and the correct IMEI is set. It worked once before but only one time.
My questions are: Am I missing some crucial command? Does the APN have to be set only for connecting to a cell?

Thanks in advance for any help.

Problem fixed. It turned out that I was using the wrong operator id. The one that was read out from the sim did not work.

Which Provider-ID did you use? Which net ?

Thanx
Holger